Owenoceras sp.

Dernov, Vitaly, 2022, Late Bashkirian Ammonoids From The Mospyne Formation Of The Donets Basin, Ukraine, Fossil Imprint 78 (2), pp. 489-512 : 505-506

? Owenoceras sp.

Text-fig. 11f

2016 Pseudobisatoceras sp. ; Dernov, text-fig. 4.

M a t e r i a l. One poorly preserved specimen from stratigraphic level 1 of the Mospyne Formation.

D e s c r i p t i o n. Specimen IGSU-4/1367 is a poorly preserved crushed fragment of a steinkern. The surface of the conch is covered with delicate lirae and very thin lamellae that intersect to form a reticulate and crenulate pattern. The transverse lamellae form a broad, shallow lateral sinus and a low projection on the ventrolateral shoulder. On the midflank, the lamellae are spaced about 0.5 mm apart. The constrictions broad, concavo-convex with a high ventrolateral projection and very shallow ventral sinus; they are clearly visible on the ventrolateral shoulder, but poorly visible on the flank. The suture line has a broad, V-shaped rectangular pointed adventive lobe and a broad, domelike dorsolateral saddle. The suture line is not preserved on the venter, ventrolateral shoulder, umbilical wall and dorsum.

R e m a r k s.? Owenoceras sp. differs from O. bellilineatum MILLER et OWEN, 1940 in the less pointed adventive lobe; the conch surface ornamentation in? Owenoceras sp. and O. bellilineatum is very similar.? Owenoceras sp. is distinguished from O. orulganensis POPOW, 1960 by its ornamentation of greater relief.

O c c u r r e n c e. Late Bashkirian, Mospyne Formation, Donets Basin ( Ukraine).

Figures

Text-fig. 11.?Agastrioceras sp., dorsal view (a), lateral view (b), ventral view (c); specimen IGSU-7/389. Scale bar 10 mm.